Cardiac Arrhythmias Liu Pinming( 刘品明 ), M.D., Ph.D., Department of Cardiology Second Affiliate Hospital Sun Yat-sen University

Useful Expressions Cardiac arrhythmias 心律失常 Sinus arrhythmia 窦性心律失常 Antiarrhythmic drugs 抗心律失常药 Atrial premature beat (APBs) 房性早搏 Atrioventricular junctional premature beat 房室交界性早搏 Ventricular premature beat (VPBs) 室性早搏

Useful Expressions Paroxysmal supraventriculat tachycardia (SVT) 阵发性室上性心动过速 Atrioventricular nodal reentrant tachycardia (AVNRT) 房室结内折返性心动过速 Atrioventricular reentrant tachycardia (AVRT) 房室折返性心动过速 Atrial tachycardia 房性心动过速 Atrial reentrant tachycardia 房性折返性心动过速 Autonomic atrial tachycardia 自律性房性心动过速 Chaotic/Multifocal atrial tachycardia 紊乱性 / 多源性房性心动过速

Useful Expressions Proxysmal ventricular tachycardia (VT) 阵发性室速 Nonsustained VT (lasting for < 30 s) 非持续性室速 Sustained VT (lasting for ≤ 30 s) 持续性室速 Atrial flutter 心房扑动 Atrial fibrillation 心房颤动 Ventricular flutter 心室扑动 Ventricular fibrillation 心室颤动

Useful Expressions Pre-excitation (Wolff-Parkinson-White) syndrome 预激综合征 (WPW) Sinus bradycardia 窦性心动过缓 Sinus arrest/standstill 窦性停搏 Sinoatrial block 窦房阻滞 Sick sinus syndrome, SSS 病窦综合征 Bradycardia-tachycardia syndrome 慢 - 快综合征

Useful Expressions Atrioventricular block (AVB) 房室传导阻滞 Intraventicular block 室内传导阻滞 Aberrant conduction 传导阻滞 Bundle branch block 束支阻滞 Bigeminy/ Trigeminy 二联律 / 三联律 Tachyarrhythmias 快速型心律失常 Bradyarrhythmias 缓慢型心律失常

Arrhythmias Definition: An arrhythmia is an abnormality of rate, regularity, or site of origin of the cardiac impulse or a disturbance in conduction that causes an abnormal sequence of activation.

Mechanisms Responsible for Arrhythmias Abnormalities of impulse generation A. Alterations of normal automaticity B. Abnormal automaticity C. Triggered activity Early/Delayed afterdepolarization Abnormalities of impulse conduction A. Reentry: 1. Unidirectional block; 2. Anatomic or functional reentrant circuit ; 3. wavelength B. Conduction block Combined abnormalities of impulse generation and conduction

Diagnostic Approaches to Arrhythmias History and physical examination ECG Ambulatory ECG recording: Holter recording Excise ECG: treadmill test Trans-esophageal electrophysiological study Invasive electrophysiological study (EPS)

Management of Arrhythmias Antiarrhythmic drugs Cardiac pacemakers DC cardioversion/defibrillation Implantable cardioverter/defibrillater (ICD) Radiofrequency catheter ablation Surgical operation

Classification of Antiarrhythmic drugs (Vaughan-Williams) Class Ⅰ : Sodium channel blockade Ⅰ a: phase 0 depression, 2+; repolarization, + Ⅰ b: phase 0 depression, +; repolarization, - Ⅰ c: phase 0 depression, 3+; repolarization, ± Class Ⅱ : Beta-adrenergic blockade Class Ⅲ : Repolarization prolongation Class Ⅳ : Calcium channel blockade

Atrial fibrillation: common causes Coronary artery disease Hypertensive heart disease Valvular heart disease, mitral stenosis Thyrotoxicosis

Atrial fibrillation: ECG characteristics Absence of P waves Very irregular baseline, f waves, with a rate of bpm, best seen in V1, Ⅱ Irregular QRS complex rate, usually normal shape

Atrial fibrillation: auscultation features Variation in the intensity of S1 Extremely irregular heart rate Pulse deficit

Atrial fibrillation: classification and management strategies Paroxysmal (<24-48hr): preventing further attacks Persistent: attempting restoration of sinus rhythm Permanent: offering good control of ventricular rate

Atrial fibrillation: treatment Etiological therapy Restoration of sinus rhythm paroxysmal: beta-blocker, propafenone, cedilanid, amiodarone persistent: drugs, DC Control on ventricular rate digoxin, betablocker Prevention of thromboembolism aspirin or ticlipidine, warfarin

Paroxysmal SVT- AVNRT & AVRT ECG features Sudden initiation and termination Fixed relationship between p the wave and QRS complex, with p often superimposed in ORS-T Regular rate of bpm Narrow QRS complexes unless there is a aberrant ventricular conduction or pre-existing bundle branch block

Paroxysmal SVT: treatemnt Vagal maneuvers: Valsalva maneuver or carotid sinus massage First choice of drugs: adenosine 6-12 mg iv, or verapamil 5 mg iv Preferred choice of drugs: propafenone 70 mg iv; cedilanid mg iv DC cardioversion Radiofrequency catheter ablation

Pre-excitation syndrome Abnormal connection between the atrium and the ventricle

Pre-excitation syndrome ECG features Short PR interval Slurred upstroke of QRS complexes (the delta wave) broad QRS complexes Secondary ST-T abnormalities (reflecting modified ventricular repolarization secondary to abnormal depolariozation

Atrial flutter: characteristics Regular sawtooth like wave with a rate of bpm Ventricular response may be 1:1 (300), 2:1 (150), 3:1 (100) or 4:1 (75), etc Severity of the symptoms depends on the ventricular rate Causes are similar to atrial fibrillation

Premature beats Atrial AV junctional Ventricular Clinical considerations ECG features Management strategies

Ventricular tachycardia ECG: ≥3 VPBs in succession at a rate of bpm; suggesting VT: ventricular captures, fusion complexes Clinical: coronary heart disease, AMI; signifying myocardial damage Treatment: drugs (lidocaine amiodarone) DC cardioversion (synchronized)

Torsades de Pointes (TDP) ECG: an irregular rapid ventricular rhythm with a periodic twisting axis seen on ECG; long QT interval Etiology: congenital long QT syndrome; acquired long QT syndrome, as antiarrhythmic drugs (Class Ⅰ a, Class Ⅲ ); hypokalamia, hypomagnesemia

Torsades de Pointes management Identifying and treating any precipitating factors MgSO 4, IV; avoidance of drugs lengthening APD Atropine, isoprenaline infusion or ventricular pacing to increase heart rate Beat-blocker for congenital long QT sydrome

Ventricular flutter / fibrillation Irregular rapid ventricular depolarization No organized ventricular contractions, no pulse, loss of consciousness Most common cause: AMI, drug toxicity, electrolyte disturbances, electric shock, end stage of many disease processes Management: non-synchronized DC defibrillation, cardiopulmonary resuscitation

Sick sinus syndrome (SSS) Definition:characterized by intrinsic inadequacy of sinus node pacemaking and /or conduction failure between sinus node and the rest of the atrium Etiology: coronary heart disease, degenerative process, cardiomyopathy Clinical manifestations: insufficiency of blood supply to important organs

Sick sinus syndrome (SSS) ECG features Marked sinus bradycardia < 50 bpm measured as SNRT, SACT and IHR Sinus arrest / sinoatrial block Holter recording Bradycardia-tachycardia syndrome atrial tachyarrhythmias Probable coexistence with atrioventricular block

Cardiac arrhythmias questions? What are the common causes, ECG features, auscultation characteristics and management strategies of atrial fibrillation? Please list the management protocols of paroxysmal supraventricular tachycardia Please list the concept and ECG findings of sick sinus syndrome Please consider the differential diagnosis of wide QRS tachycardia